The present invention relates to film adhesive compositions, and more particularly to the use of film adhesive compositions in stacked die microelectronic packaging applications.
In response to an increasing demand for semiconductor packages that are smaller, yet more functional, the microelectronic packaging industry has recently begun producing packages containing at least two stacked semiconductor dice. Indeed, it is often advantageous to stack multiple dice into the same package in order to increase circuit density without increasing the area occupied on a circuit board by the integrated circuit package.
Several challenges exist with respect to producing reliable electronic components containing stacked die packages. For example, stacked die packages typically require very thin bond lines between die (e.g., less than 15 microns). In addition, it is known that adhesive fillet and resin bleed associated with many adhesive formulations contribute to unreliable component performance. Thus, adhesives used in stacked die applications ideally would provide (at a minimum bond line thickness) superior adhesive strength and conductivity (thermal and electrical) without producing adhesive fillet or resin bleed. One possible approach to address this challenging problem lies in the use of film adhesives.
Accordingly, there is a need for film adhesives which provide superior adhesive strength and conductivity when dispensed to achieve very thin bond lines in a variety of microelectronic packages, such as, for example, stacked die packages.
In accordance with the present invention, there are provided film adhesive compositions comprising at least one macromonomer having at least one unit of ethylenic unsaturation, at least one thermoplastic elastomer co-curable with the macromonomer, and at least one cure initiator. Invention compositions are useful as adhesives in the microelectronics industry. In particular, invention film adhesives may be used to produce microelectronic assemblies with very thin bond lines without compromising adhesive strength.
In a further aspect of the present invention, there are provided methods employing invention film adhesive compositions for adhesively attaching a device to a substrate, and methods employing invention film adhesive compositions for adhesively attaching at least two semiconductor dice to a substrate in a stacked arrangement.
In a still further aspect of the invention, there are provided assemblies comprising a first article adhered to a second article by invention film adhesive compositions.